Quick Answer
The answer is to run the VACUUM command. This is correct because over time, as rows are inserted, updated, and deleted in Amazon Redshift, the physical sort order degrades and deleted rows leave behind empty space, both of which force the query engine to scan more data than necessary. The VACUUM command re-sorts rows according to the table’s sort keys and reclaims that wasted disk space, directly restoring query performance. On the AWS Certified Data Engineer Associate DEA-C01 exam, this question tests your understanding of Redshift maintenance operations and often appears as a trap where candidates confuse VACUUM with ANALYZE—remember that ANALYZE only updates table statistics for the query planner, it does not physically reorganize data. A common memory tip is to think of VACUUM as the “housekeeper” that tidies up the physical storage, while ANALYZE is the “librarian” that updates the card catalog.
This DEA-C01 practice question tests your understanding of data operations and support. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company uses Amazon Redshift for data warehousing. They notice that query performance has degraded over time. Which maintenance operation should be performed to improve performance?
Run the VACUUM command
VACUUM re-sorts rows and reclaims disk space, improving query performance.
Drop and recreate the table
Why wrong: This is disruptive and unnecessary for routine maintenance.
Run the REINDEX command
Why wrong: Redshift does not use traditional indexes; it uses sort keys.
Run the ANALYZE command
Why wrong: ANALYZE updates query plans but does not physically reorganize data.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Run the VACUUM command
Option B is correct because VACUUM re-sorts rows and reclaims space, improving performance. Option A is wrong because ANALYZE updates statistics but does not physically reorganize data. Option C is wrong because REINDEX rebuilds indexes, but Redshift uses sort keys, not indexes. Option D is wrong because DROP TABLE deletes data.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Run the VACUUM command
Why this is correct
VACUUM re-sorts rows and reclaims disk space, improving query performance.
Related concept
Read the scenario before looking for a memorised answer.
Drop and recreate the table
Why it's wrong here
This is disruptive and unnecessary for routine maintenance.
Run the REINDEX command
Why it's wrong here
Redshift does not use traditional indexes; it uses sort keys.
Run the ANALYZE command
Why it's wrong here
ANALYZE updates query plans but does not physically reorganize data.
Common exam traps
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Identify which DEA-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Data Operations and Support — This question tests Data Operations and Support — Read the scenario before looking for a memorised answer..
The correct answer is: Run the VACUUM command — Option B is correct because VACUUM re-sorts rows and reclaims space, improving performance. Option A is wrong because ANALYZE updates statistics but does not physically reorganize data. Option C is wrong because REINDEX rebuilds indexes, but Redshift uses sort keys, not indexes. Option D is wrong because DROP TABLE deletes data.
Identify which DEA-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 20, 2026
This DEA-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DEA-C01 exam.
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